Not to be critical, but to use as an illustrative example from your own life, you started your challenging period owning a Nissan 350z which got 12 mpg. If you had made exactly one different decision, buying a Honda Civic instead of that 350z, and everything else was the same, you would have hit that point with a car that got 35mpg and an additional $15,000 in your bank account.
So from a learning perspective, at the time you made the purchase of the 350z, thinking about value versus cost versus future expense, knowing what you know now do you make the same choice? I am not a fan of dwelling on past decisions, they were made and they are done. But I am a huge fan of learning as much as I can from the lessons life teaches to insure I am getting full value out of that education.